Harries is back in the squad some 18 months after winning his second cap against the Wallabies in Cardiff and the 25-year-old Dragons flyer isn't planning on wasting what he sees as an unexpected opportunity.
"The call-up for Wales has been a massive bonus," Harries, who won his first cap as a replacement on the 2010 summer tour of New Zealand before rupturing knee ligaments last year, told the South Wales Argus.
"Hopefully I can play against the Barbarians and then try and get on the tour of Australia.
"I only had the last half of the season so it would be good to get another game under my belt. If I play all right in that then hopefully I will be going on the tour.
"Last year was the first big injury I'd had and I just tried to look at it positively so that when I came back I would be flying.
"I got my head right and I used the time to work on my conditioning and other aspects of my game. My first goal after coming back was to play well for the Dragons and finish the season well - I just wanted to start playing again.
"I'm keeping my head down and training well to try and get in that team now and we'll see what happens after that."
If Harries does clinch a tour place for the trip to Australia, he could be fighting with the likes of George North, Alex Cuthbert and Aled Brew for a Test spot against the Wallabies.
The former Northampton and Bedford player made his only Test start to date against the same opposition in November 2010 as Wales were beaten 25-16 by Robbie Deans' men.
Two more defeats have followed for Wales against the Wallabies - in the Bronze Medal Match at the 2011 World Cup and back at the Millennium Stadium last winter - but Harries believes beating the Tri Nations Champions in their own backyard is more realistic than ever before.
"Australia like to play with quick ball and, like all southern hemisphere sides, are tough to play against," added Harries.
"But, watching Wales playing in the World Cup and in the Six Nations, we should be more of a match for them than the last time I played. I think it'll be interesting."